Access control system is rapidly developed along with the progress of the automatic recognition technology. After the developments of the first generation of the access control technology (using keyboard passcodes), the second generation of the access control technology (using magcards), and the third generation of the access control technology (using contact-type IC cards), RFID and biometric recognition have become main access control technologies of the present day.
An access control system with biometric recognition uses human biological characteristics such as fingerprints, palmprints, voice and face as a key to access control, based upon the fact that the probability of two identical biological characteristics of two different people is less than one part per billion.
In the recent years, the progress of biometric authentication has brought a leap in the development of access control. Compared with the biometric authentication using other biometric characteristics (fingerprints, vein, iris, etc.), facial recognition is the most natural and most direct means for identification verification since it is initiative, non-invasive, user-friendly, and easily accepted.
The face-to-unlock technology allows a user to unlock an access control system of a door or a safe by facial recognition. It is well known to those skilled in the art that the face-to-unlock technology requires facial characteristics analysis based on reference facial image data and camera data. Wherein, facial characteristic analysis based on reference optical facial image data and optical camera data is a mainstream technology currently.
However, the conventional facial characteristic analysis based on 2D/3D reference optical facial image data and optical camera data has the following deficiencies.
Firstly, the security is unsatisfied due to that an imposter may be able to unlock the access control system by using a 2D image photo taken by an optical camera or a 3D dummy of a user, and such imposturous unlock by a photo, video or wax of the user is unrecognized.
Secondly, if the reference optical facial image and the optical camera image are 3D images taken by an optical camera, complex 3D algorithms are needed to extract and analyze the facial characteristics, which requires a high background process capability of the access control system. However, an access control system of a door or a safe which is powered by DC power source lacks such capability.